The present invention pertains to gap adjustors, and more particularly to an automatic gap adjustor for use in connection with a variety of devices, such as raised flooring assemblies, belt/chain tensioners and Bowden cables.
Raised flooring assemblies are increasingly utilized in commercial buildings to accommodate the passage of cabling, wiring and ductwork. Such systems typically employ a series of height-adjustable pedestals in a grid-like arrangement. The pedestals support multiple removable floor panels that are spaced apart from a sub-floor. The spacing between the removable floor panels and the sub-floor can be dictated by the volume of cabling, wiring and/or ductwork, and can include a depth of between six inches and several feet. Optionally, the raised flooring assembly may be concealed with a flooring finish such as laminate or carpeting.
One generally accepted construction for height-adjustable pedestals is disclosed in U.S. Pat. No. 7,650,726 to Jacob-Bamberg et al, the content of which is hereby incorporated into the present application by reference. In this construction, each pedestal includes a hollow upright stanchion, a stem extending from partially within the stanchion, and a nut threadably engaged with the stem and bearing against the upper edge of the stanchion. The upper end of the stem can include a bracket for rigid attachment to four panels at their respective corners. Pedestal height can be adjusted with the clockwise or counterclockwise rotation of the nut about the stem. For example, as the nut translates downwardly along the stem while bearing against the stanchion, the stem increasingly extends from the stanchion to increase the pedestal height, and thus the height of the overlying floor panels. Conversely, as the nut translates upwardly along the stem while bearing against the stanchion, the stem recedes within the stanchion to decrease the pedestal height.
Repeated use of the raised flooring assembly can in some instances cause a gap to form between the upper edge of the stanchion and the lower edge of the nut. In this condition, the nut does not bear against the upper edge of the stanchion. Instead, the stem and the nut are generally suspended in position by the overlying floor panels. As persons and objects traverse the overlying floor panels, the floor panels can deflect downwardly to repeatedly drive the nut against the upper edge of the stanchion. The resulting instability is especially noticeable due to an undesirable clicking or knocking sound at each downward deflection of the overlying floor panels.
Known methods for correcting the above condition typically include a manual rotation of the nut until it bears against the upper edge of the stanchion. However, this method can involve the removal of floor finishing and floor panels, in addition to a manual inspection of each pedestal until the deficient pedestal is identified. Moreover, this method provides no assurance that further gaps will not develop after the deficient pedestal is adjusted. For example, the sub-floor can warp over time, resulting in further potential gaps between stanchions and nuts that would normally require a further inspection and adjustment.
Other devices, including mechanical drive belts, drive chains and Bowden cables, suffer from disadvantages similar to those of raised flooring assemblies, in that the extended use of these devices can create wear “gaps” that reduce their effectiveness. For instance, mechanical belts, such as automobile fan belts and timing belts, tend to wear and effectively lengthen over time. The wearing surfaces create a slack (i.e., a periodic gap between belt and pulley) in the belt that reduces the friction between the belt and the pulleys attached to the belt, ultimately causing the belt to slip. In addition, the lengthening of a belt or a chain can result in a loss of drive synchronization, in some instances causing the belt or chain to fall off the drive assembly altogether. Similarly, the inner cable of a Bowden cable often loses tension over time with respect to the hollow outer cable due to wear of the surfaces of moveable components to which it actuates. This creates a “gap” between the original position of the inner cable and the worn position, which reduces the linear movement of the inner cable when the cable is actuated. Retightening the inner cable is usually accomplished by lengthening the hollow outer cable by turning a stop-nut on the threaded end of the outer cable.
Accordingly, there remains a continued need for an improved system and method for the automatic adjustment of pedestals in a raised flooring assembly. In addition, there remains a continued need for a low-cost system and method for the automatic adjustment and/or prevention of gaps in a variety of other devices including for example mechanical belts, chains and Bowden cable assemblies.